My problem is related to Administrator access.I reset the Password by the 3 second reset procedure and I am then able to access via 'Admin' 'Admin'

at this stage all is fine.

I then disable DHCP and input a fixed IP address, followed by returning the NAS to my office network at this point everything works for users, and the new 'Admin' 'Admin' credentials allows me access to filestation via QNAP Cloud, and network shares

But I cannot access Administration area using the default passwords once the IP address is changed and the NAS returned to my network.

It appears to be a security issue, I do not get an incorrect message, just a constant trying to connect

Mike H wrote:But I cannot access Administration area using the default passwords once the IP address is changed and the NAS returned to my network. It appears to be a security issue, I do not get an incorrect message, just a constant trying to connect

You need to be a lot more specific in your story. What "Administration area" do you speak of? And how are you trying to access it?Do you know about the QFinder Pro tool? If yes, is QFinder Pro able to locate your NAS on your 'office network'?

If I understood the rest of your story correctly, since you are apparently able to connect to it via QNAP cloud, you now have your NAS connected to the Internet with a default admin password. Your first priority should be to change the admin password, to protect against hacking and other nefarious attacks.